Re: Field Order via Oracle ODBC

From: Arvin Meyer <a_at_m.com>
Date: Wed, 9 Jun 1999 12:43:01 -0400
Message-ID: <7jm5io$tub$1@esinet2.esinet.net>

No, that is not they way it is handled in a normalized databased.

Invoice Header -primary key = InvoiceNumber

Invoice Detail - primary key = InvoiceDetailNumber

                      foreign key  = InvoiceNumber

InvoiceLineNumber is extraneous and doesn't even need to be recorded, merely displayed for the convenience of the viewer. Composite keys should be avoided if possible in detail records, unless they are used in a join table in a many-to-many relationship.
---
Arvin Meyer
onsite_at_esinet.net

TC wrote in message <01beb294$fa0e55e0$53fa98cb_at_pentium>...
>
>Brad Pybus <brad_pybus_nospam_at_hotmail.com> wrote in article
><%%v73.1733$sk1.2500_at_client.news.psi.net>...
>> We never use multi-field primary keys.
>
>
>But how can you avoid so doing?
>
>In any master/detail relationship, the detail record will normally need a
>composite primary key, namely:
>* the master key of the parent table, plus
>* the extra field which distinguishes the child records for a given master.
>
>For example:
>* Invoice Header -primary key = InvoiceNumber;
>* Invoice Detail - primary key = (InvoiceNumber, InvoiceLineNumber).
>
>Yes? No?
>
>TC
>(No email)
Received on Wed Jun 09 1999 - 11:43:01 CDT